Redmine

Hi,
I tray to set up e-mail on Redmine 2.3.3, and after click on "e-mail test" I get: error (no implicit conversion of true into String)

Email server MS Exchange.
I have 2 instalation of Redmine 1.1.3 and 2.0.3 both of them work fine with this server.
Now I tray to upgrade 1.1.3 to 2.3.3 - all work fine except e-mail

configuration.yml:
development:
email_delivery:
delivery_method: :smtp
smtp_settings:

1. tls: false
   enable_starttls_auto: true
   address: "MS Exchange server"
   port: 587
   authentication: :login
   domain: "domain"
   user_name: "xxx"
   password: "xxx"

attachments_storage_path: /opt/redmine/files